The goals of this research program are to gain a clearer understanding of the biologic principles that govern the normal function and the pathologic responses of the corneal endothelium and to develop a method for long-term corneal preservation. Human eyes will be studied in vivo whenever possible. Clinical specular microscopy and quantitative fluorophotometry will be used to study morphologic and functional aspects of the corneal endothelium in normal eyes and others that have been subjected to trauma, surgery, disease and drug therapy. Chronic morphologic changes in endothelial cells after intraocular surgical procedures (corneal transplantation, cataract extraction, intraocular lens implantation) will be studied. Quantitative fluorophotometry with a newly developed scanning ocular fluorophotometer with improved precision will be employed to measure changes in endothelial permeability to fluorescein caused by aphakia in transplanted corneas and by topical corticosteroid therapy in Fuchs' dystrophy. The relationship between endothelial cell size and permeability to fluorescein will be studied in normal human subjects of various ages and in cats after endothelial wounding. Endothelial pump sites will also be measured in the cats. Based on preliminary experiments, a new method of corneal cryopreservation will be developed with dog, cat, and human corneas in vitro using supravital staining, corneal swelling rate measurements, and electron microscopy. The suitability of the cryopreserved corneas for transplantation will be tested by penetrating keratoplasty, first in cats and then in humans.